/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.factory.annotation;

import org.springframework.beans.factory.wiring.BeanWiringInfo;
import org.springframework.beans.factory.wiring.BeanWiringInfoResolver;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * {@link org.springframework.beans.factory.wiring.BeanWiringInfoResolver} that
 * uses the Configurable annotation to identify which classes need autowiring.
 * The bean name to look up will be taken from the {@link Configurable} annotation
 * if specified; otherwise the default will be the fully-qualified name of the
 * class being configured.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see Configurable
 * @see org.springframework.beans.factory.wiring.ClassNameBeanWiringInfoResolver
 * @since 2.0
 */
public class AnnotationBeanWiringInfoResolver implements BeanWiringInfoResolver {

    @Override
    @Nullable
    public BeanWiringInfo resolveWiringInfo(Object beanInstance) {
        Assert.notNull(beanInstance, "Bean instance must not be null");
        Configurable annotation = beanInstance.getClass().getAnnotation(Configurable.class);
        return (annotation != null ? buildWiringInfo(beanInstance, annotation) : null);
    }

    /**
     * Build the BeanWiringInfo for the given Configurable annotation.
     *
     * @param beanInstance the bean instance
     * @param annotation   the Configurable annotation found on the bean class
     * @return the resolved BeanWiringInfo
     */
    protected BeanWiringInfo buildWiringInfo(Object beanInstance, Configurable annotation) {
        if (!Autowire.NO.equals(annotation.autowire())) {
            return new BeanWiringInfo(annotation.autowire().value(), annotation.dependencyCheck());
        } else {
            if (!"".equals(annotation.value())) {
                // explicitly specified bean name
                return new BeanWiringInfo(annotation.value(), false);
            } else {
                // default bean name
                return new BeanWiringInfo(getDefaultBeanName(beanInstance), true);
            }
        }
    }

    /**
     * Determine the default bean name for the specified bean instance.
     * <p>The default implementation returns the superclass name for a CGLIB
     * proxy and the name of the plain bean class else.
     *
     * @param beanInstance the bean instance to build a default name for
     * @return the default bean name to use
     * @see org.springframework.util.ClassUtils#getUserClass(Class)
     */
    protected String getDefaultBeanName(Object beanInstance) {
        return ClassUtils.getUserClass(beanInstance).getName();
    }

}
